Re: [PATCH 1/1] mm/vmalloc.c: eliminate extra loop inpcpu_get_vm_areas error path
From: kautuk.c @samsung.com
Date: Fri Nov 18 2011 - 22:32:55 EST
Oh yes, I missed that out. :)
We should also do that.
Do you need me to redo this patch with this change ?
Although, I do notice that you seem to have already accepted this patch.
On Fri, Nov 18, 2011 at 2:59 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, 18 Nov 2011 17:13:50 +0530
> Kautuk Consul <consul.kautuk@xxxxxxxxx> wrote:
>
>> If either of the vas or vms arrays are not properly kzalloced,
>> then the code jumps to the err_free label.
>>
>> The err_free label runs a loop to check and free each of the array
>> members of the vas and vms arrays which is not required for this
>> situation as none of the array members have been allocated till this
>> point.
>>
>> Eliminate the extra loop we have to go through by introducing a new
>> label err_free2 and then jumping to it.
>>
>> Signed-off-by: Kautuk Consul <consul.kautuk@xxxxxxxxx>
>> ---
>> mm/vmalloc.c | 3 ++-
>> 1 files changed, 2 insertions(+), 1 deletions(-)
>>
>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>> index b669aa6..1a0d4e2 100644
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -2352,7 +2352,7 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
>> vms = kzalloc(sizeof(vms[0]) * nr_vms, GFP_KERNEL);
>> vas = kzalloc(sizeof(vas[0]) * nr_vms, GFP_KERNEL);
>> if (!vas || !vms)
>> - goto err_free;
>> + goto err_free2;
>>
>> for (area = 0; area < nr_vms; area++) {
>> vas[area] = kzalloc(sizeof(struct vmap_area), GFP_KERNEL);
>> @@ -2455,6 +2455,7 @@ err_free:
>> if (vms)
>> kfree(vms[area]);
>> }
>> +err_free2:
>> kfree(vas);
>> kfree(vms);
>> return NULL;
>
> Which means we can also do the below, yes? (please check my homework!)
>
> --- a/mm/vmalloc.c~mm-vmallocc-eliminate-extra-loop-in-pcpu_get_vm_areas-error-path-fix
> +++ a/mm/vmalloc.c
> @@ -2449,10 +2449,8 @@ found:
>
> err_free:
> for (area = 0; area < nr_vms; area++) {
> - if (vas)
> - kfree(vas[area]);
> - if (vms)
> - kfree(vms[area]);
> + kfree(vas[area]);
> + kfree(vms[area]);
> }
> err_free2:
> kfree(vas);
> _
>
>
>
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